Special busy test for telephone-lines.



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c, s. WINSTON.

ml Mamas Firms: at. minim. n. r

UNITED PATENT OFFICE.

SWITUHBOARD & SUPPLY PORATION OF lLLINOIS.

COMPANY, OF CHICAGO, ILLINDIS, A COR- SPECIAL BUSY TEST FOR TELEPHONE-LINES.

Specification of Letters Patented July 10, 3906.

Application filed December 23, 1904, Serial Ho; 237.911.

To on whom it may concern.-

Be it known that I, CHARLES S. WINSTON,' a citizen of the United States, residing in Chicage, county of Cook, and State of Illinois, have invented certain new and useful Ireprovements in Special Busy Tests for Talephone-Lines, of which the following is a specification.

My invention relates to. improvements'in apparatus to he used in connection with teie phone systems, and more particniarly'to ap aratus to enable the operator to become inol'med of the condition of the telephone-lines with which subscribers desire to be connected for conversation.

The obj ect of my invention is to provide a special busy test for the subscribers lines, whereby when the operators perform the usual operations of testing the lines to determine their idle or busy condition the said test is made manifest to them and they are thus informed of the special condition of the line. This apparatus may be used in various ways and for various urposes; but one special service to which t e invention is particularly applicable is in connection with the telephone-lines of an exchange upon which troule exists and which are temporarily out of commission. The special test is applied to such lines whereby as soon as the operator makes the usual busy test she is informed of the fact that the line is temporarily in disuse and is thereby enabled to so inform the call.- ing subscribers. It is apparent that in case no such special, test is rovided the operator is unable to receive ei er the ordinary bus test or to call the subscribers located on cue lines, whereby she loses considerable time in ielipeatedly ceiling such parties and eventuy is enable to give a satisfactory ex lanation to the waiting subscribers of the ailure of such parties to respond. By the use of my 7 invention such waste of time and labor and" annoyance is avoided, since upon receiying such special test the operator can immediately make the proper explanation to the waiting subscribes.

My invention is illustrated in'the accompanyin drawing, in which the figure is a die-* am 0 the central-office end 0 a commontesting end of an operators cord-circuit, as well as'of the special testing apparatnsthat is required for such s ecial busy test.

In the figure, L in icates a subscribe'rs line pretending in two limbs 2 and Kirforn the subscrihers station to the central ofiice, where they terminate in the springs 4 and 5 of a cohort relay R, the normal contact of the former spring bein grounded, while the simi- "ia'r'contsct of the%atter spring is connected "bye conductor 6 with one terminal of the winding of the line-relay R", whose other terminal is joined by a conductor 7 with a hattery-lead 8, extending from the live pole of the central common battery B. The said line-relay-controls the local circuit of the linesignal S, which is preferably in the form of a small incandescent lamp. The forward contacts of said cut-ofi-rela springs 4 and 5 are connected with the switchboard-section jack, such as Jfand a plurality of multip e acks, such as J and J the latter being provided'in V desired number, according to the size of'tli'e switchboard.

The cord-circuit, of which the connecting or calling end'only is shown, comprises in the latter a calling-plug P, having tip and-sleeve contacts adapted to register, res ectively, with the corresponding contacts of t c springjacks of the lines when inserted therein. The tip-contacts of the two plugs of the cord-cirsuit (the answeringlug not heing shown) 7 are joined'bythe flexible strands tend i and interposed condensers c while their 'sieeye eontacts are similarly oined hy the strands s and s and the interposed condensers eryisory relay 1' is connected upon one side by conductor 11 with the strand t" and npon the other side 0 conductors 12 and iji with the grounded po e of the battery B. 'Similarbr a cooperating sn erviso relay r is connected on o e side b 0011 uctor 14 with the strand 8 nd u on t e other side by conductors ll igilfiis wit the live pole of the battery Bi" Thus the two relays, with the battery B interposed are bridged across the calling end of the cord-circuit. The said two relays serve, as shown, to control the local attery subscribers line and the calling or circuit of the supervisory signal S", associated of the telephone-line comprising the two condoctors 9 and 15, "leading to an answer V with this end of the cord-circuit, said relay 7 serving to norm allyclose the said local circuit and the relay r to normally open the same. The relay 1 is provided with an additional spring 16, connected with the forward portion of the strand t and which in its forward position completes the two portions of the strand for conversation. The normal contact of said spring is connected through a suitable conductor 17 with a test-relay 1", preferably of high resistance and impedance and whose other terminal is grounded. The spring 18 of said. test-relay serves when attracted to close a path for current from ground at said relay through conductor 19, a retardation-coil 20, the tertiary windin of the operators induction-coil, and by con uctors 22 and to the live pole of the battery B. A condenser c is connected upon one side with the conductor 17 and upon the other by conductor 23 to a point between the retardation-coil and the third winding of the operators induction-coil 21. The arrangement of this retardation-coil 20 and the condenser c in the operators busy-testing circuit permits the special test to be receive by the operator, as will be hereinafter described. The operators head-receiver 24, a suitable condenser c, and the secondary winding of her induction-coil 21 are adapted to be bridged across the cord-circuit, preferably the answering end thereof, by means of the listening-key spring 25 and the conduc tors 26 and 27, leading therefrom to the strands t and s. The operators transmitter 28, together with the retardation-coil 29, condenser c and the primary winding of her induction-coil 21, are suitably arranged in the usual manner to be charged from the battery B. A ringing-generator 30 is adapted to be connected between round and the tip-contact of the plug by t 1e operation of the ringing-key springs 31, the sleeve-contact of the plu being at the same time connected with the ive pole of the battery B by means of conductor 32, includin a suitable resistance 33. In order to produce a special test which may be received by any of the operators provided with the above-described apparatus, I provide the apparatus shown at the lower side of the diagram, which includes an induction -coil I, the primary of which is included in a local circuit with the battery B, to ether with a suitable device (indicated at for ra idly interrupting said local circuit and which may consist of a rapidly-rotating disk and contact-brush suitably arranged to make and break the circuit at a high rate. The secondary winding of said coil, which has one terminal joining the corresponding terminal of the primary winding, has its other terminal connected, through a suitable resistance-coil 36 and a flexible strand 15 with the sleeve-contact of a plug P, adapted to fit and be inserted in the jacks of any of the lines and when so inserted to make contact with the test-ring of the jack. When, therefore, the special testing-plu such as P is inserted in one of the jacks o the line as, for instance, jack J a rapidly-alternating current is impressed upon the sleeve side of said line. At the same time current flows from the battery B over conductor 8, through the secondary winding of coil Z, and thence over strand t through the on t oii' relay R to ground, thus operating the latter rclay and preventing the operation of the linesignal in any way, as by a crossing of the linewires or a ground upon the line. Now when a call is received from a subscriber for a con nection with. a line upon which such a special source of current has been impressed and the operator proceeds to test the line with her calling-plug in the usual manner the application of the tip P to the test-ring of a jack of said line results in a flow of such rapid alternating current from such secondary winding of the induction-coil I, through resistance 36, over strand t, the sleeve side of the line tested, the tip of the plug P, the forward portion of the strand t of the testin -cord, spring 16 of relay 1, conductor 17, an thence through the condenser 6 the tertiary winding of t 1e operator's coil 21, conductors 22, 15, and 8,

back to the other terminal of the secondary 5 coil. The passage of this rapidly-alternating current through the operators inductioncoil produces a tone in her receiver which is distinct from the ordinary busy test and from which she knows the special condition of the line and can so inform the waiting subscriber. Such alternating current does not flow through the test-relay r due to its high impedance, and since said relay is operated at this time, due to the flow of battery-current therethrough, it will not pass back through the retardation-coil 20 and spring 18 direct to ground, due to the impeding effect of said coil 20.

The invention is thus thought to be made clear, inasmuch as the remainder of the apparatus is that ordinarily employed in one common type of two-wire system, and the operation of interconnecting the subscribers on such lines for conversation is well understood. In practicing my invention a plurality of plugs, such as plug P are provided, as is indicated by the branching lines at 37, the inductioncoil I and interrupter 35, as well as the battery, being common to the plugs. These plugs are ordinarily under the charge of one person, who as soon as trouble on a line is reported inserts one of the plu s in a jack of the line, where it remains untiI the trouble is cleared. The invention is applicable to different classes of service and may be embodied in other concrete forms Without avoiding the scope or principle of the same. I therefore do not wish to be understood as limiting myself in all respects to the special details shown and IIC is thus informed of the condition of described, but, elude all such modifications and alterations as fairly fall within its purview.

1. In a telephone system, the combination with telephone-lines terminating at the central oflice in the usual spring-jacks and having cut-oil relays actuated over portions of the talking-circuits for rendering the linesignals inoperative, of a special testing a paratus provided with connectingplugs a apted to be inserted in the said spring-j acks, said apparatus being arranged to impress a distinctive current upon the test-contacts of the jacks and at the same time to furnish current over the talking-circuits for the operation of the cut-oil relays of the lines with which said plugs are connected, and test-re ceiving devices associated with the operators cord-circuits responsive to such distinctive current, through a path 0 aque to steady currents and responsive to t e ordinary lousy test throu h a path opaque to the distinctive current, wherein y when the operator makes th e usual busy test of the line she is informed of theispecial condition of the line, substantially as described.

2. In a telephone system, the combination with tele hone-lines provided with springjacks an cut-oil relays operated by current over a portion of the talking-circuit, of a special testing ap aratus provided with a connecting-plug a apted to be inserted in a spring-j ac of any of the lines, said apparatus eing arran ed to impress u on the testing terminals 0 the line with which the plug is connected a rapidl -varying current of one direction of flow on y for the operation of the cut-off relay of the said line, an operators cordcircuit, and test-receiving devices associated therewith responsive to such rapidlyvarying currents through a path opaque to stead currents and responsive to the ordinary usy test through another path, whereby when a line having such testing a paratus applied thereto is tested in the usua manner t e operator receives a distinctive signal and the line, substantiall as described.

3, In a telbphone system, the combination with telephone-lines provided with testin terminals and cut-off relays all conductively associated with thetalking-circuit of the lines, of a special testing apparatus adapted to be connected with the lines to im ress upon the testing terminals an unsteady distinctive current and at thesame time to furnish current over the talking-circui ts for the operation of the cut-off relays, a cord-circuit, a test-receiving device associated with the cord-circuit responsive to such distinctive current over a path opaque to stead currents and to steady currents over a pat opaque to said distinctive current, whereby whenthe special apparatus is connected with a line and the on the contrary, hold it to inoperator makes the usual busy test she receives adistinctive si nal and is thus informed of the condition of t c line tested, substanti ally as described.

4. In a telephone system, the combination with telephone-lines having busy-testing terminals and cut-oh relays connected with the talking-circuits of the lines, of a special testin apparatus having a connection plug ac ipted to be inserted in a spring-jack of any line, a steady source of current and a source of rapidly-varying current included in said apparatus and adapted upon the insertion of the plug into a sprin -jack of a line to inn press thereon a singleirection pulsating current serving for the operation of the cut-ell relay of the line and for testing, a cord-circuit, an operators test-receiving induction-coil associated therewith, a condenser in the circuit with said test-receiving coil and intercepting the metallic connection between said (701 and the ti strand of said cord-circuit, and a relay oi high inductance normally connected between said tip-strand and ground and adapted to be actuated only by stead currents whereby the varying currents wi 1 pass through the condenser and coil to give one form of signal to the operator, and the said currents will pass through the relay and actuate it and a conductor connected with contaste of said relay and with the said induction-coil whereby the actuation of said relay gives another form of signal to the operator, substantially as described.

5. In a telephone system, the combination with telephone-lines having testing-tennis nals, of special testing apparatus adapted to be connected with the lines and to impress upon the testing-terminals a rapidly-varying current, an operators cord-circuit, a busytesting circuit completed over a strand thereof, said circuit including electromagnetic apparatus through which the usual testing-current is adapts to flow, and a condenser connested in series with said testing-circuit and in parallel with said electromagnetic device to provide a path for the rapidly-varying current in case a line to which said special testing apparatus is appliedis tested, whereby the distinctive test 1s received by the operator and she is thus informed of the special condition of the line, substantially as described 5. in a telephone system, the combination with a telep one-line having testing-terminals connected with the talking-circuit thereof, of special testing apparatus adapted to be connected with the line to impress upon the testing-terminals a rapidly-varying current, an operators cord-circuit having a testingcircuit completed over a strand thereof and containing a coil of high impedance to prevent a sudden variation of potential upon the tclephonedine in making the usual busy test, and a condenser connected with said testing-circuit in advance of said coil to prol the lines and a test-receiving apparatus vide a ready path for the rapidly-varyin adapted to receive a varying-current test currents, whereby the operator is enabled 1 over one path, and. a steady-current test also to receive the distinctive test caused by l over another path, substantially as described. the said rapidly-varying currents when test- Signed by me at Chicago, county of Cook, ing a line to which such special testing appal and State of Illinois, in the presence of two ratus has been applied, substantially as de- Witnesses. scribed. CHARLES S. WINSTON.

7. In a telephone system, the combination \Vitnesses:

ROBERT LEWIS Areas,

with telephonelines, of a varying-currentl l EDITH F. GRIER.

test producer adapted to be connected with 

